Artificial Intelligence is pretty darn cool, but if you think of how smart it can become, you'll start to rethink the entire concept of machines being able to learn, act, and be very close to being human...
Think of a computer virus that would turn the internet into one big AI. What do you think would happen? Would it give the world even more information, or would it try to take over the world destroying the Human race in the process? AI has potential to help people with their daily lives. But, the potential of it terminating us all is much higher. That sounds pretty scary. Being destroyed by our own creation.
With that being so, why do we still pool all our knowledge and resources into something potentially dangerous? Well, I don't really know the answer to that question. Human beings, for the longest time, create things that we know will probably hurt us in the long run.
If AI gets to the point where we cannot control it, that's when we should probably pull the plug before all the termination stuff.
Maybe creating AI will make us feel like there is someone else besides ourselves in the universe. Just the thought of knowing there are neighbors that aren't human stirs the mind into a large imaginative powerhouse. That's why the "what if" question still remains on if AI can help us.
In my opinion, AI will probably inherit some of the best human traits, making it more like an average person rather than a horrifying Matrix type character. The only problem with that is that AI technology is still in its infancy and it will probably evolve very quickly in the next thirty or so years making Apple's Siri code look like someone banged his head on a keyboard. With today's computational power, AI probably would come to the conclusion that the problem with people is people and start the apocalypse. But as more an more advancements, like quantum computing, start moving a long the intelligence will be more human than machine and it will create a new age for human and machine.